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Hitachi 50EX20B 50" Rear Projection Television Questions & Answers
My screen goes blank after about 30 seconds or so, any ideas?
about the only common issue (if model listed here is correct) is bad solder connections at the vertical output IC.Usually in this case jarring the set will cause it to try to open and allow the picture--if no vertical sweep (pic top to bottom) set will blank all 3 tubes to prevent an instant burn mark on them.
My picture gets smaller and the picture shakes,
Mark,by now your TV has many, many bad grounds and weak to bad capacitors. If you know anything about electronics, heat is the number one enemy of TVs. If you can pull out the convergence board, you will see many ICs, transistors, jumpers, resistors and diodes etc, in dire need of resoldering. It takes a very keen eye to find these. The next board under consideration would be the power supply. Once again bad grounds and weak to bad capacitors are here.If you feel you can repair this, please find a good soldering pen. I would suggest you purchase a soldering pen from an electronic specialist. Do not purchase the soldering pen that has a screw located near the tip of the pen. These are unregulated and will make for almost an impossible good soldering. You will need ab ESR meter to find bad capacitors. Your best repair would be to find an electronic hobbiest to repair this, if you can not! Thanks for asking, and show a few hands of support!
Hitachi 50ex20b shuts of
Hi, you need to stop running the set , call a tech and have him do some solder re-work, this is a cheap, easy fix, keep running it that way and it will become an expensive fix, gl, video-tek
CONVERGENCE
Check for bad resistors low ohms near your STKs big black ics.
No picture or sound
Remove the rear panel. With the TV on you should see a red LED near the center of the PCB. There should also be 5 green leds, 3 to the left a 2 behind. If there is no red leds, check the fuses. If there are no green leds or maybe 1 or 2, disconect PSD5. It's a connector on the left side of the power board that connects to the audio board. It's the 3rd on fro the back. It's labled. With that disconected, turn on the set and look for the green leds. If all 5 light, the power supply is OK and you have a problem beyond that. If they don't all light you have a bad power supply.
CAN NOT LINE UP THE CONVERSIONS ON CORN OF TV
Depending on what you have done so far after replacing STKs it can take up 6 hrs to realine complete convergence on these sets and if your DCU moduel is bad cost is 215.00 This type of alinment requires someone who knows what they are doing .
Does Not Turn On
I actually ended up with this set. It turned out to be a very nasty short circuit on the audio board. To trouble shoot disconnect PSD5 to isolate the power supply. It's the 3rd connector from the back on the left side of the power supply. If you turn on the tv and now see 5 green leds and the one red led, look for a short outside of the power supply. The short on this set was on the left side of the audio board (which is to the left of the power supply) There was a wire add and a part add covered in wax. The bare wire was touching a ground but you have to remove the wax to see it. Since this may be a change that was made to all sets of this model, it may be a common failure. Good Luck all.
Hitachi 50EX20B Bigscreen TV
You can download a PDF from here:
http://www.servicemanuals.net/results.aspx?type=SM&brand=0&model=50EX20B
Make sure that the coolant is not leaking out onto the printed circuit boards. i have had the remote sensor cause this problem before and also I have had bad capacitors in the sweep and the main power supplies. Good Luck
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